The apartment was great, the location *extremely* convenient, we had everything we need and there were no issues with our host, or any problems at all with the apartment itself. There was also a pool that was great for our daughter.
The only reason I'm giving this 4 and not 5 stars is the apartment building had extremely aggressive signage at the entrance telling us that short term stays such as airbnb are illegal, and we could be arrested or fined. My guess is that there is some dispute between the building owners and the apartment owners over short term stays. I'm guessing it is also because of this that the host arranges a pickup so that we could be driven into the apartment basement avoiding the need to walk past reception pulling luggage....
So although everything worked out fine for us, and I very much doubt we would actually have been arrested or fined, we were left with a sense of discomfort every time we walked in or out of the building, and once, chatting to someone in the lift we were asked if we'd just moved in, and I had to give a vague answer... I'm aware airbnbs in many locations skirt the edges of legality, but frankly, that should not be the guests' problem.
Anyway, if you read the above and think I'm making a fuss about nothing, this apartment is highly recommended for Bangkok, based on the excellent location - covered walkway to the BTS, 7-11 in the building, and a lot of good restaurants nearby if you don't want to venture further afield.